Perl has a command-line flag, -P (capital P), which sends its input script through the C pre-processor before perl compilation. I can't recall ever hearing of anybody actually using it, though it's obviously there for a reason, and this sounds like as good a reason as any. (Note that perldoc perlrun warns, 'Because both comments and cpp directives begin with the # character, you should avoid starting comments with any words recognized by the C preprocessor such as "if", "else", or "define".' Also note that you can't define values on the command line; -D sets debugger flags.)